1. Field of the Invention
The present invention relates to a device for planting seeds in the ground, comprising an inlet orifice which is connected to a pipe via which an airstream transporting the seeds arrives, an outlet orifice via which said seeds are planted in the ground and a device for separating said seeds from the airstream that transports them.
The invention also relates to a pneumatic seeder equipped with devices as described herein above for planting seeds in the ground.
2. Discussion of the Background
Such a planting device is known from patent application EP 080 912. The device for separating the seeds from the airstream consists of a cyclone. This cyclone is located at the end of a pipe which opens into it tangentially. The stream of air transporting the seeds arrives via this pipe. At its upper part, the cyclone has an orifice via which the air escapes. It is extended downward by a tubulure through which the seeds drop under gravity into the ground. They are therefore not thrown onto the ground by the airstream.
A cyclone such as this is bulky. It is complicated and expensive to produce. In addition, to optimize its operation, a cyclone specially tailored to the size of each type of seed ought to be used, something which is barely possible in practice.
It is an object of the present invention to overcome the aforementioned drawbacks. The invention must, in particular, provide a device for planting seeds with a device for separating the seeds from the airstream that is simple, economical and easy to use for all kinds of seeds usually sown by farmers.
To this end, an important feature of the invention consists in the fact that the separating device comprises a grating which lies substantially in the continuation of said airstream and seeds inlet orifice so that a maximum of the air escapes from the planting device through this grating and the seeds are held back. Said seeds remain in the planting device and drop into the ground under the effect of their own weight, without re-bounding.
Said grating may have an inclined face intersecting the direction of the airstream. This arrangement makes it easier for the air to leave the planting device. Advantageously, at least part of the grating follows the shape of the airstream inlet orifice as closely as possible so as to prevent the seeds from being able to leave the planting device by any route other than via the outlet orifice.
According to another feature of the invention, the device for separating the air and seeds additionally comprises a canalizing device which directs the stream of air and seeds towards the grating. Practically all of the air then leaves directly through said grating. This canalizing device comprises a deflector which spreads the stream of air and seeds over a large proportion of the surface area of the grating.
Another important feature of the invention consists in the fact that the separating device is removable.
The separating device also advantageously comprises a cap which at least partially surrounds the grating. This cap protects said grating and ducts much of the air which has escaped from the planting device toward the rear of the machine.
According to another feature of the invention, the planting device additionally comprises a regulating device which ensures a substantially constant spacing between the seeds leaving via its outlet orifice. This device advantageously lies substantially vertically in line with the grating. It comprises guide elements arranged in a zigzag. It may be interchangeable so that it can be adapted to suit the type (family) of seeds to be sown.